Sheared polymer blends and process for their preparation

Abstract

A blend and a process for producing that blend in which a high ethylene content ethylene-propylene polymer and a lower ethylene content ethylene-propylene polymer are subjected to simultaneous blending and shearing to reduce their molecular weights and molecular weight distribution. The sheared blend of polymers can function as a shear stable dispersant viscosity index improver with improved lower temperature properties or the hydrocarbon base for multifunctional for viscosity index improvers, motor fuel additives or polymeric dispersants.

What is claimed is: 
     
       1. An ethylene-propylene polymer blend having a number average molecular weight within the range of about 300 to about 5,000 and a molecular weight distribution within the range of about 1.5 to about 5 prepared by the process of simultaneously, in the absence of solvent, blending and shearing: (a) an essentially amorphous low ethylene content ethylene-propylene polymer containing an ethylene to propylene mole ratio within the range of 35/65 to 65/35, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7;   (b) a partially crystalline higher ethylene content ethylene-propylene polymer containing an ethylene to propylene molar ratio within the range of about 65/35 to about 85/15, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7; whereby the blending and shearing is carried out under conditions of heat and mechanical work sufficient to create high shear conditions for a time sufficient to reduce the molecular weight and molecular weight distribution of the blend of (a) and (b), wherein the weight ratio of low ethylene content ethylene-propylene polymer (a) to the higher ethylene-propylene polymer (b) is within the range of about 80/20 to about 50/50.     
     
     
       2. A lubricating oil concentrate comprising a lubricating oil and the polymer blend of claim 1. 
     
     
       3. A lubricating oil composition comprising a lubricating oil and the polymer blend of claim 1. 
     
     
       4. A composition as defined in claim 3 wherein the composition includes a lubricating oil additive. 
     
     
       5. A polymer blend as defined in claim 1 wherein the low ethylene content ethylene-propylene polymer contains less than 3 percent by weight crystallinity and the higher ethylene content ethylene-propylene polymer has a higher degree of crystallinity of no greater than 25 percent. 
     
     
       6. A polymer blend as defined in claim 1 wherein at least one of the low ethylene content ethylene-propylene polymer and the higher ethylene content ethylene-propylene polymer includes a polyene monomer copolymerized therewith containing two or more carbon to carbon double bonds and containing 4-20 carbon atoms. 
     
     
       7. A polymer blend as defined in claim 6 wherein the polyene is selected from the group consisting of non-cyclic polyene monomers, monocyclic polyene monomers and polycyclic polyene monomers. 
     
     
       8. A polymer blend as defined in claim 1 wherein at least one of the low ethylene content ethylene-propylene polymer and the higher ethylene content ethylene-propylene polymer has been functionalized by means of a graft polymerization using a graft monomer. 
     
     
       9. A polymer blend as defined in claim 1 wherein the polymer blend is further functionalized by graft polymerization using a graft monomer. 
     
     
       10. A polymer blend as defined in claims 8 or 9 wherein the graft polymerization utilizes a graft monomer selected from the group consisting of unsaturated dicarboxylic acid anhydrides, their esters and their corresponding acids. 
     
     
       11. A polymer blend as defined in claims 8 or 9 wherein the graft polymerization is carried out using a graft monomer in the form of a derivative in the form of an acrylic or methacrylic acid containing 4 to 16 carbon atoms. 
     
     
       12. A polymer blend as defined in claims 8 or 9 wherein the polymer blend has been derivatized by reaction with a derivatizing compound containing one or more reactive groups selected from the group consisting of primary amines, hydroxyls and thiols. 
     
     
       13. A polymer blend as defined in claim 12 wherein the derivatizing compound is selected from the group consisting of alkylene polyamines, aryl polyamines, heterocyclic polyamines and combinations thereof. 
     
     
       14. A polymer blend as defined in claim 1 wherein both the low ethylene content ethylene-propylene polymer and the higher ethylene content ethylene-propylene polymer have been functionalized by grafting. 
     
     
       15. A derivatized ethylene-propylene polymer blend having a number average molecular weight within the range of about 300 to about 5,000 and a molecular weight distribution within the range of about 1.5 to about 5 prepared by the steps of simultaneously, in the absence of solvent, blending and shearing: (a) an essentially amorphous low ethylene content ethylene-propylene polymer containing an ethylene to propylene mole ratio within the range of 35/65 to 65/35, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7;   (b) a partially crystalline higher ethylene content ethylene-propylene polymer containing an ethylene to propylene molar ratio within the range of about 65/35 to about 85/15, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7; whereby the blending and shearing is carried out under conditions of heat and mechanical work sufficient to create high shear conditions for a time sufficient to reduce the molecular weight and molecular weight distribution of the blend of (a) and (b), wherein the weight ratio of low ethylene content ethylene-propylene polymer (a) to the higher ethylene-propylene polymer (b) is within the range of about 80/20 to about 50/50, reacting the polymer with a graft monomer to form a functionalized blend, and further reacting the functionalized blend with a reactive organic compound containing one or more reactive groups selected from the group consisting of primary amines, hydroxyls and thiols.     
     
     
       16. A polymer blend as defined in claim 15 wherein the reactive organic compound is selected from the group consisting of alkylene polyamines, aryl polyamines, heterocyclic polyamines and combinations thereof. 
     
     
       17. A polymer blend as defined in claim 15 wherein the reactive organic compound is an aryl polyamine selected from the group consisting of N-phenyl-phenylene diamines, N-naphthylphenylene diamines and substituted derivatives thereof. 
     
     
       18. A polymer blend as defined in claim 15 wherein the reactive organic compound is a heterocyclic polyamine selected from the group consisting of aminocarbazoles, aminoindoles, aminopyrroles, amino-indazolinones, aminoperimidines, aminomercaptotriazoles, aminomorpholines, aminopiperazines, aminopiperidines, aminophenothiazines, aminopyridines, aminopyrazines, aminopyrimidines, aminoimidizolidones, aminothiadiazoles, aminothiothiadiazoles, aminobenzotriazoles, aminoimidazoline and aminothiazolines. 
     
     
       19. A polymer blend as defined in claim 15 wherein the reactive organic compound is selected from the group consisting of a mercaptothiazole, and a mercaptobenzoimidazole. 
     
     
       20. A polymer blend as defined in claim 15 wherein the graft monomer is maleic anhydride and the reactive organic compound is a primary amine. 
     
     
       21. A polymer blend as defined in claim 15 wherein the graft monomer is selected from the group consisting of unsaturated dicarboxylic acid anhydrides, their esters, their corresponding acids, and an acrylic acid containing 4 to 16 carbon atoms and a methacrylic acid containing 4 to 16 carbon atoms. 
     
     
       22. A process for producing an ethylenepropylene polymer blend comprising simultaneously, in the absence of solvent, blending and shearing: (a) an essentially amorphous low ethylene content ethylene-propylene polymer containing an ethylene to propylene mole ratio within the range of 35/65 to 65/35, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7;   (b) a partially crystalline higher ethylene content ethylene-propylene polymer containing an ethylene to propylene molar ratio within the range of about 65/35 to about 85/15, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7; whereby the blending and shearing is carried out under conditions of heat and mechanical work sufficient to create high shear conditions for a time sufficient to reduce the molecular weight and molecular weight distribution of the blend of (a) and (b), wherein the weight ratio of low ethylene content ethylene-propylene polymer (a) to the higher ethylene-propylene polymer (b) is within the range of about 80/20 to about 50/50, with the blending and shearing being carried out such that the polymer blend has a number average molecular weight within the range of about 300 to about 5000.     
     
     
       23. A process as defined in claim 22 wherein the low ethylene content ethylene-propylene polymer contains less than 3 percent by weight crystallinity. 
     
     
       24. A process as defined in claim 22 wherein the higher ethylene content ethylene-propylene polymer has a degree of crystallinity of no greater than 25 percent. 
     
     
       25. A process as defined in claim 22 wherein at least one of the low ethylene content ethylene-propylene polymer and the higher ethylene content ethylene-propylene polymer includes a polyene monomer copolymerized therewith containing two or more carbon to carbon double bonds and containing 4-20 carbon atoms. 
     
     
       26. A process as defined in claim 25 wherein the polyene is selected from the group consisting of non-cyclic polyene monomers, monocyclic polyene monomers and polycyclic polyene monomers. 
     
     
       27. A process as defined in claim 25 wherein the polyene monomer is selected from the group consisting of 1,4-hexadiene, dicyclopentadiene, norbornadiene, 5-methylene-2-norbornene, 5-ethylidene-2-norbornene, vinyl norbornene and the alkyl norbornadienes. 
     
     
       28. A process as defined in claim 29 wherein the polyene is present within the range of about 0.1 to about 10 percent based on the total weight of the polymer. 
     
     
       29. A process as defined in claim 22 wherein at least one of the low ethylene content ethylene-propylene polymer and the higher ethylene content ethylene-propylene polymer has been functionalized by means of a graft polymerization using a graft monomer. 
     
     
       30. A process as defined in claim 29 wherein the graft monomer is selected from the group consisting of unsaturated dicarboxylic acid anhydrides and their corresponding acids. 
     
     
       31. A process as defined in claim 29 wherein the graft monomer is maleic anhydride. 
     
     
       32. A process as defined in claim 29 wherein the graft monomer is a derivative of acrylic or methacrylic acid containing 4-16 carbon atoms. 
     
     
       33. A process as defined in claim 32 wherein the graft monomer is selected from the group consisting of glycidyl methacrylate, methacrylate, methylmethacrylate, ethylmethacrylate and aminopropylmethacrylate. 
     
     
       34. A process as defined in claim 29 wherein the graft monomer is a vinyl amine containing 2-25 carbon atoms. 
     
     
       35. A process as defined in claim 34 wherein the vinyl amine is selected from the group consisting of allylamines, N-vinylpyridines, N-vinylpyrrolidones, vinylcarbazoles, vinylimidazole and vinylthiazoles. 
     
     
       36. A process as defined in claim 29 wherein the graft monomer is selected from the group consisting of vinyl silanes and vinylbenzyl halides. 
     
     
       37. A process as defined in claim 29 wherein the graft monomer is present in an amount within the range of 0.1 to 6 percent based on the total weight of the polymer. 
     
     
       38. A process as defined in claim 29 which includes the step of derivatizing the blend with a derivatizing compound containing one or more reactive groups selected from the group consisting of primary amines, hydroxyls and thioles. 
     
     
       39. A process as defined in claim 38 wherein the derivatizing compound is selected from the group consisting of alkylene polyamines, aryl polyamines, heterocyclic polyamines and combinations thereof. 
     
     
       40. A process as defined in claim 22 wherein the simultaneous blending and shearing is carried out at a processing temperature within the range of 150° to 350° C. 
     
     
       41. A process as defined in claim 22 wherein the simultaneous blending and shearing is carried out in a mixer having the capability of effecting mechanical work to reduce the molecular weight and the molecular weight distributions. 
     
     
       42. A process for producing an ethylenepropylene polymer blend comprising simultaneously, in the absence of solvent, blending and shearing: (a) an essentially amorphous low ethylene content ethylene-propylene polymer containing an ethylene to propylene mole ratio within the range of 35/65 to 65/35, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7;   (b) a partially crystalline higher ethylene content ethylene-propylene polymer containing an ethylene to propylene molar ratio within the range of about 65/35 to about 85/15, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7; whereby the blending and shearing is carried out under conditions of heat and mechanical work sufficient to create high shear conditions for a time sufficient to reduce the molecular weight and molecular weight distribution of the blend of (a) and (b),   wherein the weight ratio of low ethylene content ethylene-propylene polymer (a) to the higher ethylene-propylene polymer (b) is within the range of about 80/20 to about 50/50, and reacting the polymer blend with a graft monomer to form a functionalized blend, and further reacting the functionalized blend with a reactive organic compound containing one or more reactive groups consisting of primary amines, hydroxyls and thioles to form a derivatized polymer blend, having a number average molecular weight within the range of about 300 to about 5,000.     
     
     
       43. A process as defined in claim 42 wherein at least one of the low ethylene content ethylene-propylene polymer and the higher ethylene content ethylene-propylene polymer includes a polyene monomer copolymerized therewith containing two or more carbon to carbon double bonds and containing 4-20 carbon atoms. 
     
     
       44. A process as defined in claim 42 wherein the graft monomer is selected from the group consisting of unsaturated dicarboxylic acid anhydrides and their corresponding acids. 
     
     
       45. A process as defined in claim 42 wherein the graft monomer is a derivative of acrylic or methacrylic acid containing 4-16 carbon atoms. 
     
     
       46. A process as defined in claim 42 wherein the reactive organic compound is selected from the group consisting of alkylene polyamines, aryl polyamines, heterocyclic polyamines and combinations thereof. 
     
     
       47. A process as defined in claim 42 wherein the reactive organic compound is an aryl polyamine selected from the group consisting of N-phenyl-phenylene diamines, N-naphthylphenylene diamines and substituted derivatives thereof. 
     
     
       48. A process as defined in claim 42 wherein the reactive organic compound is a heterocyclic polyamine selected from the group consisting of aminocarbazoles, aminoindoles, aminopyrroles, amino-indazolinones, aminoperimidines, aminomercaptotriazoles, aminomorpholines, aminopiperazines, aminopiperidines, aminophenothiazines, aminopyridines, aminopyrazines, aminopyrimidines, aminoimidizolidones, aminothiadiazoles, aminothiothiadiazoles, aminobenzotriazoles, aminoimidazoline and aminothiazolines. 
     
     
       49. A process as defined in claim 42 wherein the derivatizing compound is selected from the group consisting of a mercaptothiazole, and a mercaptobenzoimidazole. 
     
     
       50. An ethylene-propylene polymer blend having a number average molecular weight within the range of about 1,000 to 12,000 and a molecular weight distribution within the range of about 1.5 to about 5 prepared by the process of simultaneously, in the absence of solvent, blending and shearing: (a) an essentially amorphous low ethylene content ethylene-propylene polymer containing an ethylene to propylene mole ratio within the range of 35/65 to 65/35, having a number average molecular weight within the range of about 20,000 to 150,000 and a molecular weight distribution within the range of about 2 to 7;   (b) a partially crystalline higher ethylene content ethylene-propylene polymer containing an ethylene to propylene molar ratio within the range of about 65/35 to about 85/15, having a number average molecular weight within the range of about 20,000 to 150,000 and a molecular weight distribution within the range of about 2 to 7; whereby the blending and shearing is carried out under conditions of heat and mechanical work sufficient to create high shear conditions for a time sufficient to reduce the molecular weight and molecular weight distribution of the blend of (a) and (b), wherein the weight ratio of low ethylene content ethylene-propylene polymer (a) to the higher ethylene-propylene polymer (b) is within the range of about 80/20 to about 50/50.     
     
     
       51. A derivatized ethylene-propylene polymer blend having a number average molecular weight within the range of about 1,000 to about 12,000 and a molecular weight distribution within the range of about 1.5 to about 5 prepared by the steps of simultaneously, in the absence of solvent, blending and shearing: (a) an essentially amorphous low ethylene content ethylene-propylene polymer containing an ethylene to propylene mole ratio within the range of 35/65 to 65/35, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7;   (b) a partially crystalline higher ethylene content ethylene-propylene polymer containing an ethylene to propylene molar ratio within the range of about 65/35 to about 85/15, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7; whereby the blending and shearing is carried out under conditions of heat and mechanical work sufficient to create high shear conditions for a time sufficient to reduce the molecular weight and molecular weight distribution of the blend of (a) and (b), wherein the weight ratio of low ethylene content ethylene-propylene polymer (a) to the higher ethylene-propylene polymer (b) is within the range of about 80/20 to about 50/50, reacting the polymer with a graft monomer to form a functionalized blend, and further reacting the functionalized blend with a reactive organic compound containing one or more reactive groups selected from the group consisting of primary amines, hydroxyls and thiols.     
     
     
       52. A process for producing an ethylene-propylene polymer blend comprising simultaneously, in the absence of solvent, blending and shearing: (a) an essentially amorphous low ethylene content ethylene-propylene polymer containing an ethylene to propylene mole ratio within the range of 35/65 to 65/35, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7;   (b) a partially crystalline higher ethylene content ethylene-propylene polymer containing an ethylene to propylene molar ratio within the range of about 65/35 to about 85/15, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7; whereby the blending and shearing is carried out under conditions of heat and mechanical work sufficient to create high shear conditions for a time sufficient to reduce the molecular weight and molecular weight distribution of the blend of (a) and (b), wherein the weight ratio of low ethylene content ethylene-propylene polymer (a) to the higher ethylene-propylene polymer (b) is within the range of about 80/20 to about 50/50, with the blending and shearing being carried out such that the polymer blend has a number average molecular weight within the range of about 1,000 to about 12,000.     
     
     
       53. A process for producing an ethylene-propylene polymer blend comprising simultaneously, in the absence of solvent, blending and shearing: (a) an essentially amorphous low ethylene content ethylene-propylene polymer containing an ethylene to propylene mole ratio within the range of 35/65 to 65/35, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7;   (b) a partially crystalline higher ethylene content ethylene-propylene polymer containing an ethylene to propylene molar ratio within the range of about 65/35 to about 85/15, having a number average molecular weight within the range of about 20,000 to about 150,000 and a molecular weight distribution within the range of about 2 to 7; whereby the blending and shearing is carried out under conditions of heat and mechanical work sufficient to create high shear conditions for a time sufficient to reduce the molecular weight and molecular weight distribution of the blend of (a) and (b), wherein the weight ratio of low ethylene content ethylene-propylene polymer (a) to the higher ethylene-propylene polymer (b) is within the range of about 80/20 to about 50/50, and reacting the polymer blend with a graft monomer to form a functionalized blend, and further reacting the functionalized blend with a reactive organic compound containing one or more reactive groups consisting of primary amines, hydroxyls and thioles to form a derivatized polymer blend, having a number average molecular weight within the range of about 1,000 to about 12,000.